Typically, printing on a substrate is performed with reflective inks and/or toners using, for example, an ink-jet or laser printer, respectively. In toner systems, reflective colors are produced by the reflection of light of one or more wavelengths by toner printed on a substrate. Multiple color reflective toners may be applied to a substrate in differing amounts to produce a variety of reflective colors. The colors reflected are determined by the electromagnetic energy (i.e., light) that the toner on the substrate absorbs or otherwise subtracts from the light incident on the toner. The subtractive primary colors commonly used in reflective color printing are cyan, yellow, and magenta. Such a printing system is referred to as a CYMK model. In printing with component C, Y, and M reflective toner compositions, colors of hues other than cyan, yellow, and magenta can be produced by combining the subtractive primary colors in differing amounts on the substrate to combine the absorption of each primary color. The incident light not absorbed is reflected to produce reflected light of a particular color. For example, a reflective cyan toner composition absorbs certain wavelengths of incident visible light and reflects the non-absorbed remaining visible light having wavelengths corresponding to the color cyan. In another example, a reflective yellow toner composition absorbs certain wavelengths of incident visible light and reflects the non-absorbed remaining visible light having wavelengths corresponding to the color yellow. Combining the subtractive absorption of a reflective yellow toner and a reflective cyan toner can produce a reflective light having wavelengths corresponding to a green color. Combination of colors (e.g., inks, toners) in printing may occur by a variety of known processes including, but not limited to, stochastic screening, traditional line screening, half-toning, dithering, pixelation, and any combinations thereof.
In reflective printing using cyan, yellow, and magenta reflective toner compositions, the C, Y, and M image components may be combined to produce the absorption of substantially all visible wavelengths and reflecting a black color. Alternatively, a CYMK model (where the “K” represents the “key”) may include a fourth reflective black toner composition as the key for producing reflective black color in printing.
Another color model, the RGB model, is based on additive properties of the colors red (R), green (G), and blue (B), from which many colors and hues may be produced. The CYMK and RGB models have been correlated by known processes in traditional reflective printing (e.g., in digital computer printing processes utilizing software correlations and/or conversions).